Re: sufficent proof for primes of the kind p:=x^2+x+1
- --- In email@example.com, "leavemsg1" <leavemsg1@...>
> --- In firstname.lastname@example.org, "Bernhard Helmes" <bhelmes@>
> > A beautifull evening,
> > I try to give you a sufficent proof for primes p:=x^2+x+1
> > p:=x^2+x+1=x*(x+1)+1 with p = 3 mod 4 => 2 appears only one time
> > divisor of p-1But p=241 is not congruent to 3 (mod 4). So it is not a counter-
> > p mod 3 = 1 or in other words 3 | p-1
> > p mod 9 > 1 => 3 appears only one time as divisor of p-1
> > 2 ^ ((p-1)/2) = p-1 mod p, must be verified
> > then p is prime
> Hi, Bernhard.
> I think that x=15 is a counter-example... 2^((240/2)) == 1 mod 241.
> Is it? Bill
Buenos Aires - Argentina